Cessna 172 fuel selector

On Jan 29, 3:09 pm, Ross wrote:

It was rather difficult given the two small inspection plates you had to
work though. Then the fact that we had to take the handle position side
off the pedestal to get the whole thing out. After this it should be
good for another 40 years.

Actually, Cessna's 200-hour inspection requirements call for
removal of all those inspection plates in the floor, among many other
things, so that cables and pulleys and fuel and brake lines and the
structure and that valve can be inspected. Every time we buy another
used 172 we find that none of this stuff has been looked at, sometimes
in 30 years. The amount of gunk in the belly, wear and damage that's
obviously been there a long time, and corroded fasteners all tell the
story. We've found fuel strainers that appear to have never been
apart. That's a 100-hour thing. We find cracked rudder hinge brackets,
a common 172 fault, and cracked stabilizer forward spars, another
common problem caused by people pushing the tail down to turn the
airplane. The bottom end of the aft doorposts will crack, too,
especially if operated off rougher strips, and you can't find that
without taking the interior out. We find the bulkhead at the aft end
of the baggage compartment cracked. We find the aluminum fuel tubing
chafed halfway through above the doors and in the aft doorpost, caused
by rubbing on the structure. If that starts leaking in flight you
can't stop it. On those same tubes as well as the vent crossover line
there are short pieces of rubber hose that need replacing every ten
years or sooner. We find those rotten and ready to split. We very
often find cracked exhaust components, something there's no excuse for
whatever, since the cowling's off anyway to change the oil.
We've found crossed trim and elevator cables in Citabrias that
were installed like that, one at the factory, one after a major
rebuild, and all frayed because they were rubbing on each other.
That's a 100-hour requirement, looking at that stuff, and in neither
airplane were they caught before we bought them.
Good maintenance costs money. But it pays off in the end by
avoiding having to replace badly-worn or damaged stuff that could have
been caught and quickly remedied years earlier. It's like cancer:
catch it soon enough and you might live a long life.

Dan